growth and development (dr. mercado) Flashcards
What is interstitial growth?
growth inside of the tissues
interstitial and appositional growth is a combo of ___________, ___________ and ___________.
hyperplasia, hypertrophy, secretion of ECM
What type of growth occurs at ALL points within the tissue?
interstitial
the cranial base is formed by _________ growth.
interstitial
if the extracellular matrix is NOT mineralized, ___________ growth may continue in soft tissues and cartilages.
interstitial
which type of growth only occurs at the surface of bones?
appositional
what are two examples of interstitial growth?
all soft tissues, cartilage
appositional means____________.
addition to surfaces
what are examples of appositional growth?
bony surfaces of cranial vault, maxilla and mandible
which type of growth occurs via cells of the periosteum?
appositional
when the secreted ECM is mineralized, what is formed?
bone
can interstitial growth occur within bone?
NO
what is endochondral growth?
bone growth within cartilage, cartilage transformed into bone
during endochondral bone growth, where are the ossification centers?
within cartilage
what are two examples of endochondral bone growth?
chondrocranium (ethmoid, sphenoid, and basioccipital bones), epiphyseal plate of long bones
what is intramembranous growth?
secretion of bone matrix within or between connective tissue membranes
what type of bone growth does NOT have a cartilage intermediate and does NOT replace cartilage?
intramembranous
what is an example of intramembranous growth?
desmocranium (cranial vault, maxilla and mandible)
in relation to Meckel’s cartilage, where does intramembranous formation of bone occur?
just lateral to it
what kind of cartilage does condylar cartilage arise from?
independent secondary cartilage
which type of remodeling changes the shape of bone?
surface remodeling
which type of remodeling allows bone to adapt to mechanical stress?
internal remodeling
which type of remodeling allows for calcium and phosphate exchange?
internal
T/F: surface remodeling occurs at the surfaces of growing endochondral AND intramembranous bone.
TRUE
T/F: internal remodeling results in resorption in one area and apposition in the other.
FALSE, appositional
when vascular channels within bones bring ostercytes to the area, ___________ remodeling is occurring.
internal
growth site of craniofacial complex
cranial base, cranial vault, nasomaxillary complex, mandible
syndochondroses of the cranial base are __________ joints .
cartilaginous
____________ growth at the sydochondroses results in cranial base lengthening.
endochondral
the enlargement of the sphenoid bone is due to _________ remodeling.
surface
the thre most important synchondrosis are ….
spheno-ethmoid, inter-sphenoidal and spheno-occipital
direct ossification occurs in _________.
sutures
re-active (secondary growth) occurs in _________.
sutures
active (primary growth) occurs in____.
synchondrosis
the nasomaxillary complex is formed entirely through __________ ossification.
intramembranous
nasomaxillary growth occurs by ______ and _______.
apposition, surface remodeling
the maxilla translates ______ and _______ away from the cranial base during growth.
down and forward
what elongates the maxilla during growth?
apposition at circum-maxillary sutures
while bone is being resorbed at the __________, apposition occurs at the _______ and _______. this causes palate to move mostly downward and widen transversely.
floor of the nose, palate and alveolar process
maxillary apposition of bone occurs at the _____________.
maxillary tuberosity
which surface (anterior or posterior) surface of the maxilla is resorbed?
anterior
EXECPT at ________, the mandible grows via surface apposition and remodeling
condylar cartilage, which grows by endochondral growth
mandible translates _____ and _____ away from cranial base.
down and forward
what are the two principle growth sites of the mandible?
posterior surface of ramus, condylar and coronoid processes
surface remodeling of the mandible allows the body to grow ________ and the ramus to grow_________.
longer, higher
surface remodeling of the mandible allows more room in the mandible for ____________.
molars to erupt
what is a growth site?
a location where growth occurs
what is a growth center?
a location where INDEPENDENT growth occurs
What are the major points and conclusion of the suture theory?
all tissues that form bone have intrinsic potential to do so, growth centers genetically controlled; sutures and periosteum are growth sites. sutures react rather than act independently. NO evidence for this theory
what are the major points and conclusion of cartilage theory?
all cartilages are growth centers (i.e. cartilage in mandibular condyle controls growth of mandible); cranial base synchondroses and nasal septum act s independent growth centers pushing maxilla forward, mandibular condyle is merely growth site. PARTLY supported with evidence
major points of functional matrix theory
heredity and genes play NO role, face growth occurs based on fxnl needs mediated by soft tissues, ALL tissues that form bone are growth sites (microcephaly vs. hydrocephaly). PARTLY supported with evidence
fxnl matrix theory clinical applications
mandibular ankylosis, rapid maxillary expansion, distraction osteogenesis
growth of ______ is a response to growth of brain. what are growth sites?
cranium, sutures and periosteum
growth of _______ is a result of endochondral growth at synchondroses. what is growth center?
cranial base, synchondroses
growth of _______ is primarily a result of apposition and remodeling as the is translated by soft tissues. what are growth sites?
maxilla, sutures and periosteum
growth of _________ may result from endochondral growth at nasal septum cartilage (growth center)
maxilla
growth of ________ occurs by endochondral growth at condyle and surface remodeling of bone is translated by soft tissues. what are growth sites?
mandible, condyle and periosteum
What does Scammon’s growth curve show us?
different tissue system of the body grow at different rates
